Is it true that Elise has no counters?

Elise has a few counters. One of them, ironically enough, is Time itself. She falls off hard late-game.

All have more than enough tools to negate Elise.

elise does have counters because at the end of the day her % hp damage still gets reduced by magic resist calculations. A tank with more focus on magic resist than health would ultimately take less damage. Also, around the midpoint of your health bar is when Elise has the hardest time dealing damage with her Q. Other than that it's just a matter of outplaying her gap closing.

Nocturne is a Pretty big counter as well. Not only can he spell shield her abilities, but his fear still procs even if she rappals.

How does % damage have to do with having no counters? If this were the case then Vayne and Fiora would have no counters. I have like 200k on Elise and can surely say that she gets countered plenty. Think of Yasuo or Irelia for a second. They can dash to her spiderlings, which happen to follow behind her. Think of champions that have DoTs, so she can't rappel the damage like Malzahar, Teemo, Brand, etc. Think of champions that can sustain all her damage like Ivern. Elise is actually one of the most well balanced champions in the game and the last time she was ever OP was at the start of Season 6 with Runic Echoes giving her so much damage and movespeed.

Raid. OFF! An old slipper

Take your pick